LABS was conceived to address important issues in bariatric surgery and metabolism in the obese and morbidly obese. LABS aims to explore relationships of patient characteristics, clinical conditions, serologic and genetic markers, process of care, and clinical, psychosocial and health economic outcomes. The primary achievements of LABS in its first 5 years have been to define the domains of exploration, identify appropriate metrics and enroll 5105 participants in LABS land achieve vital status data for 99% due for at 30 days post-surgery. In addition, 1947 participants in LABS 2 have been recruited with data collected for 91% for 6 months follow-up. An extension of LABS would build on the rigorous research infrastructure across 10 clinical sites at the 6 clinical centers representing several care delivery systems and patient populations. LABS enrolls patients from 6 academic and 4 community hospitals undergoing operations by 33 surgeons. These sites have created a cohort with considerable diversity of important patient characteristics. LABS includes 21% males (range across sites 16% to 32%), 9% Black/African-Americans (range 0% to 24%), 7% Hispanics (range 1% to 16%), 10% age 60+ years (range 5%-18%), and 10% BMI 60+ kg/m2 (range 6% to 27%). These features have been linked to short and long-term outcomes and represent critical subgroups that have not been adequately characterized because they appear infrequently in most single-center cohorts. Importantly, the diversity across sites is more likely to represent the bariatric surgery population in the U.S. than would be possible from any individual site. RELEVANCE (See Instructions): Critical scientific advantages of the multi-center LABS consortium compared to single-center studies include: 1) The ability to recruit a larger number of patients, in a comparable, or shorter, period of time and 2) A research infrastructure with rigorous data collection practices, high levels of data accuracy and completeness, rigorous follow-up, and a comprehensive database of clearly defined data elements.